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MAP Goals
Antoinette14   7
N an hour ago by Rice_Farmer
What's yall's MAP goals for this spring?
Mine's a 300 (trying to beat my brother's record) but since I'm at a 285 rn, 290+ is more reasonable.
7 replies
Antoinette14
Yesterday at 11:59 PM
Rice_Farmer
an hour ago
Warning!
VivaanKam   25
N 2 hours ago by jb2015007
This problem will try to trick you! :!:

25 replies
VivaanKam
May 5, 2025
jb2015007
2 hours ago
Lines concur on bisector of BAC
Invertibility   2
N 3 hours ago by NO_SQUARES
Source: Slovenia 2025 TST 3 P2
Let $\Omega$ be the circumcircle of a scalene triangle $ABC$. Let $\omega$ be a circle internally tangent to $\Omega$ in $A$. Tangents from $B$ touch $\omega$ in $P$ and $Q$, such that $P$ lies in the interior of $\triangle{}ABC$. Similarly, tangents from $C$ touch $\omega$ in $R$ and $S$, such that $R$ lies in the interior of $\triangle{}ABC$.

Prove that $PS$ and $QR$ concur on the bisector of $\angle{}BAC$.
2 replies
Invertibility
3 hours ago
NO_SQUARES
3 hours ago
Renu would take $15$ days working $4$ hours per day to complete a certain task w
Vulch   3
N 4 hours ago by Capybara7017
Renu would take $15$ days working $4$ hours per day to complete a certain task whereas Seema would take $8$ days working $5$ hours per day to complete the same task. They decide to work together to complete this task. Seema agrees to work for double the number of hours per day as Renu, while Renu agrees to work for double the number of days as Seema. If Renu works $2$ hours per day, then the number of days Seema will work, is
3 replies
Vulch
Today at 1:44 PM
Capybara7017
4 hours ago
The best math formulas?
anticodon   18
N 4 hours ago by anticodon
my math teacher recently offhandedly mentioned in class that "the law of sines is probably in the top 10 of math formulas". This inspired me to make a top 10 list to see if he's right (imo he actually is...)

so I decided, it would be interesting to hear others' opinions on the top 10 and we can compile an overall list.

Attached=my list (sorry if you can't read my handwriting, I was too lazy to do latex, and my normal pencil handwriting looks better)

the formulas
18 replies
anticodon
Yesterday at 11:00 PM
anticodon
4 hours ago
Mathcounts Stories
Eyed   180
N 4 hours ago by Capybara7017
Because Mathcounts season is over, and I think we are free to discuss the problems, I think we can post our stories without fear of sharing information that is not allowed.
Hopefully this does not become too spammy, and I hope to see good quality stories. For example, I am not looking to see stories like this, or this.
Instead I would like to have higher quality stories.
Mods if this is not ok, then feel free to lock, I just hope we can all share our reflections on this contest, since mathcounts is now over.
Anyway, here's mine (At the request of Stormersyle)

old locked mathcounts stories thread
180 replies
Eyed
Jun 3, 2019
Capybara7017
4 hours ago
9 zeroes!.
ericheathclifffry   9
N 4 hours ago by Capybara7017
i personally have no idea
9 replies
ericheathclifffry
May 5, 2025
Capybara7017
4 hours ago
24 Game Strategies
Ljviolin11   1
N 4 hours ago by Capybara7017
Hello everybody! Probably most of you have heard of Game 24: You are given 4 numbers and you must add, subtract, multiply, and divide these numbers to achieve 24.
For example: 11, 9, 4, 7.
Solution
I am participating in a Game 24 contest soon. I have been using this online simulator to practie: https://www.4nums.com/. Sometimes, I can get the answer really quickly, but other times, it takes me a couple of minutes. Are there any general strategies that you have used for this game that you would recommend? Thank you very much!
1 reply
Ljviolin11
Today at 2:27 PM
Capybara7017
4 hours ago
prime numbers
wpdnjs   118
N 5 hours ago by Capybara7017
does anyone know how to quickly identify prime numbers?

thanks.
118 replies
wpdnjs
Oct 2, 2024
Capybara7017
5 hours ago
Calculate the distance AD
MTA_2024   0
Today at 3:50 PM
A semi-circle is inscribed in a quadrilateral $ABCD$. The center $O$ of the semi-circle is the midpoint of segment $AD$. We have $AB=9$ and $CD=16$.
Calculate the distance $AD$.
0 replies
MTA_2024
Today at 3:50 PM
0 replies
9 What is the best way to learn math???
lovematch13   93
N Today at 3:04 PM by ReticulatedPython
On the contrary, I'm also gonna try to send this to school admins. PLEASE DO NOT TROLL!!!!
93 replies
lovematch13
May 22, 2023
ReticulatedPython
Today at 3:04 PM
construction of line knowing newton line direction
PROF65   7
N Jan 7, 2023 by ancamagelqueme
Source: own?
Let $ABC$ be a triangle and $\ell ,d \   $ be two lines .
Construct a line $DE$ s.t. $D\in AB,E\in AC ,DE\parallel d $ and the newton line of $ DBCE$ is parallel to $\ell$.
RH HAS
Best regards.
7 replies
PROF65
Jan 4, 2023
ancamagelqueme
Jan 7, 2023
construction of line knowing newton line direction
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G H BBookmark kLocked kLocked NReply
Source: own?
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PROF65
2016 posts
#1 • 1 Y
Y by GeoKing
Let $ABC$ be a triangle and $\ell ,d \   $ be two lines .
Construct a line $DE$ s.t. $D\in AB,E\in AC ,DE\parallel d $ and the newton line of $ DBCE$ is parallel to $\ell$.
RH HAS
Best regards.
This post has been edited 2 times. Last edited by PROF65, Jan 5, 2023, 1:20 AM
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youthdoo
1312 posts
#2
Y by
What is a construction you mean?
Compasses and straightedge?
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PROF65
2016 posts
#3
Y by
youthdoo wrote:
What is a construction you mean?
Compasses and straightedge?

exactly
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PROF65
2016 posts
#4
Y by
any idea
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youthdoo
1312 posts
#5
Y by
Do we just have to show that it is possible?
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GeoKing
518 posts
#6 • 1 Y
Y by PROF65
Sol:- Construct $H$ the orthocenter of $ABC$. Construct line $\ell'$ through $H$ perpendicular to $\ell$. Construct the line through $A$ perpendicular to $d$ and let it intersect $\ell'$ at $H'$. Let the line though $H'$ perpendicular to $AC,AB$ meet $AB,AC$ respectively at $ D,E$ . These are the required points.
Note that the construction works because steiner line and newton line are perpendicular and using this we constructed $H'$ the orthocenter of $ADE$ and using that we finally constructed $D,E$
This post has been edited 1 time. Last edited by GeoKing, Jan 6, 2023, 4:34 AM
Reason: latex
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PROF65
2016 posts
#7 • 1 Y
Y by GeoKing
another way
the isogonal of $M$ ,the miquel point of $ BCED$ is the infinity point of the newton line so we can construct $ M$ then we draw a line parallel to $d$ through $C$; it hits $(ABC)$ at another point say $G$ let the line $MG$ cuts $AB $ at point that is exactly $D$ . Finally we draw a parallel to $d$ to construct $E$.
RH HAS
Best regards.
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ancamagelqueme
104 posts
#8
Y by
Quote:
Given three lines $a, b, c$ and two vectors $\vec{u}, \vec{v}$, construct a line $d$, with direction $u$, such that Newton line of the quadrilateral formed by the four lines $a, b, c, d$ has direction $\vec{v}$.

The three lines $a, b, c$ form a triangle $ABC$. Let ${\mathcal P}$ be the parabola inscribed in its medial triangle and whose axis has the direction of the vector $\vec{u}$. Let $d$ be the conjugate diameter of the direction of the vector $\vec{v}$. ${\mathcal P}$ and $d$ intersects at a point $T_{uv}$. The tangent at $T_{uv}$ to ${\mathcal P}$ is Newton's line of the quadrilateral $abcd$, which has the direction of the vector $\vec{v}$.

Apple GeoGebra
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